Load driving and braking apparatus



June 22,1954

s. J. sPuRGEoN 2,681,717 LoAD DRIVING AND DRAKING APPARATUS Filed Dec. 30, 1950` 2 Sheets-Sheet l June 22, 1954 s. .1. sPuRGEoN 2,681,717

LOAD DRIVING AND BRAKING APPARATUS Filed Dec. 30, 1950 2 Sheets-Sheet 2 F11 7 JNVENTOR.

Patented June 22, 1954 UNITED STATES PATENT OFFICE 7 Claims.

My present invention relates to apparatus for transmitting driving power from a prime mover to a load and to such apparatus which shall embody means for braking and stopping the load by dissipating a considerable portion of the energy thereof during the period of actual brakmg.

This invention iinds particular application for use in driving conveyers of the belt type, although as will be pointed out its use is not limited to such apparatus. However, for the purpose of illustrating the invention it will be described in association with a belt conveyer.

As is well understood, the inertia (WR2) of a moving load such as a loaded conveyer belt makes the stopping of such a belt a very di'icult operation. This is especially true if the belt, which may be from a few hundred yards to a few miles in length, travels down grade or over hilly terrain. If material is continually fed onto a belt at the up grade end, the force of gravity adds to the inertia, resulting in a figure for the expression WR2 which is tremendously large. Heretofore, the driving apparatus for such belts has been equipped with various forms of brakes for stopping the belt, including, among others, solenoid actuated brakes. In practice it has been found that the inertia of even medium length conveyor belts is so great that the brake bands of the brakes heretofore used were of unsually short life. In some instances the linings have been known to wear away completely within a matter of days, the precise time depending, of coursepon the number of times the belt is stopped as well as on many other factors.

YIn seeking to overcome the above and other difliculties I have discovered that through the use of a slip type drive mechanism such as a fluid drive, magnetic coupling, or the like between theprime mover and the load together with two brakes, one on either side of the fluid drive, I canmaterially reduce the wear on the brake bands. i

The prime object of my invention therefore is to provide apparatus of the character designated in which the power of a prime mover is transmitted to a load through a uid type coupling or its equivalent, in combination with brake mechanisms operatively connected to the driving and driven elements of the fluid coupling, whereby when the load is to be stopped it is accomplished by cle-energizing the prime mover, applying the brake associated with the driving element of the Huid coupling to hold it against rotation, thereby dissipating the energy of the moving load as heat in the coupling, and then in applying the brake connected to the driven element of the uid coupling, thereby bringing the load to a stand still.

A further object is to provide apparatus of the character designated in which the brake mechanism operatively associated with the driving element of the slip type drive mechanism is oi the relatively quick acting type and in which the brake mechanism connected to the driven element of the slip type drive mechanism, essentially to the load itself, is of the delayed action type, whereby the first named brake when applied is effective to immediately stop and lock the driving element against rotation, while the other brake is subsequently applied, permitting a large part of the energy of the moving load to be dissipated as heat in the slip type drive mechamsm.

A further object is to provide apparatus of the character designated in which the brake connected to the driving element of the drive mechanism may be of the delayed action type or of a type wherein the driving element is permitted to come gradually to a stop, thereby obtaining the advantages pointed out hereinafter.

Apparatus illustrating the features of my invention is shown in the accompanying drawings forming a part of this application in which:

Fig. 1 is a somewhat diagrammatic plan view showing my invention associated with the drive end of a belt conveyer;

Fig. 2 is a side elevational view of the assembly shown in Fig. 1;

Fig. 3 is a View, partly in elevation and partly in section and showing a suitable form of iluid coupling, the drawing being somewhat diagrammatic for the sake of clarity;

Fig. 4 is a side elevational view of a reduction gear unit partly broken away and in section;

Fig. 5 is a view taken generally along line V-V of Fig. 1 and illustrating a type oi brake which may be operatively connected to the driving element of the uid coupling;

Fig. 6 is a view taken generally along line VI-VI of Fig. 1 and showing an elevational view of a delayed action type of brake suitable for use in my improved apparatus; and,

Fig. 7 is a wholly diagrammatic wiring diagram.

Referring now to the drawings for a better understanding of my invention I show at l0 a conveyor belt representing the load to be driven. The belt is shown in diagrammatic manner as being trained over a driving pulley Il, suitably yindicated generally by the numeralrfl.

supported in bearings l2 and I3 on the shaft I4 oi the pulley l l. On the shaft I4 are a plurality of sheaves l or sprockets over which are trained multiple V-belts il or chains, if desired. The V-belts il pass over pulleys I8 mounted on the output shaft i9 of a reduction gear unit indicated generally by the numeral 2l.

The gear reduction unit 2| may comprise a double eXtension-input'shaft '22 having thereon a worm 25. The worm 25 meshes with a gear 25a which is fast on the shaft I9. As will be understood, the pitch of the Worm and gear are such that the shaft 22 can be rotated when the load represented by the conveyer belt lll drives the Vshaft le. In other words, the type of :gear box used is not the type involving the locking worm and gear arrangement, but on the other hand is one involving what may be termed the free Wheeling type of worm and gear drive.

.Connected to one'end of the shait .22 is the driven 4unit or section 23 of ,a fluid coupling power transmitting element unit ,indicated generally by the numeral 2. As will be understood, the fluid `coupling,mechanism comprises an outer housing, YVrepresented by the portion 23 which 'is the driven portion.

Within the housing section .2lare a plurality of blades or vanes26. Cooperating with the vanes 2t areother sets `of vanos 2l which are .keyed as at 23 toa shaft ,29. The casing or the unit is oiltight and as is Well Aknown whenV there is relative rotation between Athe vanes 2li and 2l, `hydraulic fluid within thecasing serves `to translmit power. Thus, the entire outer housing section indicated by thenumeral 23 may be delined ,for the purpose `of description as the driven ele-- kmentor `the lluid ,coupling Whereas the vanes 21 maybe describedas the driving element thereof. In practice it will be understood that the hy- `draulic coupling is capable of transmitting power in both directions, namely, the ,shaft 29 will Vbe rotated if shaft 22 becomes the vdriving element,

.andshaft22 will be rotated if shaft 29 is driven.

Industrial types of luid coupling units are well known in the .art and no further detailed description is deemed to be necessary.

The shaft 29 may be connected through a flex- .ibleooupling .3l to `one end of the rotor shaft 32 of an electric motor prime .mover 33.

The other extending end A32a of the rotor shaft 32 :is keyed to a brake drum ,35 forming a part of an instantaneous solenoidactuated brake unit While various forms of brakes may be employed, inisome instances I prefer -to use a magnetic brake of vthe solenoid type in which the solenoid is energized to ,release the brake. When de-energized a. spring 36 applies the brake .through the linkage .illustrated in Fig. 5. It will be understood that the armature 3l of the solenoid 38 is pivotally connected at 39to the Alinkage system illustrated. A suitable type of solenoid actuated brake is described in DescriptiveBulletin No. 15-340, dated `July 1943, issued ;by the VWestinghouse Electric Corporation, Buffalo, New York. As is understood in the art for the operation of such devices, f'

when the solenoid 33 is energized the brake is released, and when de-energized the spring 36 suddenly returns the unit to full braking position.

The opposite end of the shaft 22 projecting from the gear box unit 2| may be keyed to the `brake drum it of a delayed action type of brake M.- gA sui-table form of brake of this type is also disclosed in the above mentioned bulletin. In general, the unit lll comprises a small electric motor 42 which drives a hydraulic pump (not 'l shown) disposed in a suitable housing 43. When energized the motor drives the pump, pumping :duid in such manner as to cause a yoke le to move upwardly due to its connection at 4t to piston rods ll', thus to release the brake. When the motor d2 is oie-energized, a spring E applies the brake. However, the action of the spring 48 is gradual due to an adjustable metering valve in the `hydra-linie system (not shown), with the eifect that the brake is gradually applied, bringing the shaft 22 to a gradual stop.

In Fig. 7 I show diagrammatieally a wiring diagram in which the motors "it and 42 and the solenoid 38 are shown in a common circuit.

.Power is supplied to the three units through the lines fit and El and is under control of a switch Z52. Assuming that the switch 52 is in the position shown, all of the electrical mechanisms are cle-energized. When the switch is closed the solenoid 38 is energized, releasing the brake 34 and motor t2 is energized releasing brake ylll. By the same action motor 33 is energized, driving the load. Y i

From the foregoing the method of Vconstructing and using Ymy improved apparatus may lnow be explained and understood. With the apparatus assembled as illustrated and as described Yand when Aswitch 52 is closed, 'it will be Iseen that motor ,33 drives the conveyor belt 'through the fluid coupling unit 24, the reduction gear box 2i and belts ll'. When itis desired to stop theload the switch 52 is moved to open position. This de-energizes the motor 33 andsolenoid 3E of the brake unit tl. This permits Athe spring "it to suddenly apply the brake of the-unit 34, locking the vanes 2l against rotation. The motor lli is also fie-energized when the switch 52 is opened. Due to the delay action eilect of the unit-lll, the brake thereof iSJlOpled gradually. In the meantime, that is, between the time the brake "5d -is locked and before the brake il! is locked, the housing '23 of the hydraulic unit 24 carrying blades 26 is'still rotating due to the vdriving action of the load through the belts Il, shaft i9, -gear 25a-and Worm 25. A large part of the energy of the moving load is thereby dissipated in the Vmechanism 24 rin the form of heat. Therefore,

by the time brake '4l has completely set t0 lock the shaft 22 against further rotation and hence completely stop the conveyer belt lua large part of the energy ofthe moving load has been expended. The wear and tear on the brake bands of both the units 3s and MV is thus reduced to a minimum. Further, whenrthe vbrake il is locked it will be apparent that the load likewise is looked.

Although l. have shown a quick acting brake 34 of the solenoid type operatively connected to the driving element of the coupling, it will be understood that I may, in certain cases, employ a diferent type of brake mechanism. For instance, I may employ one of the delayed action types of brakes ll in -place of the instantaneous type 34, or in other words, employ two of the units 4l. In this case, 'by suitably timing the braking action of vthe unit associated with the driving element of the iiuid coupling, I can gradually bring the driving element of the fluid coupling to a stop. This substitution of brake types iinds particular application in installations for driving and stopping very heavy loads vsuch as long conveyer belts. It is understood that the amount of torque transmitted by `a iiuid type coupling is a function of the slippage lbetween the driving and driven elements thereof. Thus, by gradually applying a brake like the one indicated at 3A and which is connected to the driving element of the unit 24, I can gradually reduce thespeed of the elements 21, thereby obtaining `innite slippage ratios, thus obtaining a wide range of stopping torque varying from a minimum at minimum slippage to a maximum at lock position of elements 21. Obviously, if forms of magnetic brakes are employed the above result can be obtained by properly controlling the flux density therein.

When employed as drive means for a conveyer belt, my invention eliminates sudden stopping of the belt. This in turn eliminates the tendency of the belt to pull vertically away from the idlers as has been the case heretofore where a belt traversing hilly terrain was brought to a stop with existing brakes. My improved drive thus reduces strain on the belt and supporting means therefor, permitting the use of lighter belts and driving mechanisms, and reducing the initial and maintenance costs of belt conveyers.

From the foregoing it will be apparent that I have devised an improved apparatus for driving and braking moving loads. My improved apparatus .provides a smooth drive as well as a smooth braking arrangement and one which reduces materially the stress and strain on the various parts involved. The component parts of the apparatus have proved in service to be practical and trouble free when operating within the load ranges prescribed therefor.

In this speciiication and in the appended claims the expression slip type drive mechanism means any of the several types of mechanisms in which force is transmitted without actual mechanical connection between the driving anddriven elements thereof. Examples of such mechanisms are iiuid couplings, ordinary electro-magnetic couplings and that magnetic type embodying ferrous particles suspended in a suitable fluid medium.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are specilically set forth in the appended claims.

What I claim is:

l. In load driving and braking apparatus, the combination with a prime mover and a slip type drive mechanism having driving and driven e1ements interposed in power transmitting relation between the prime mover and the load, of brake mechanism operatively connected to that element of the slip drive mechanism which isdriven by the prime mover, a second brake mechanism operatively connected to that element of the slip drive mechanism which is connected to the load, means to apply the iirst named brake to hold the associated element of the slip drive mechanism against rotation, an-d means to apply the second named brake after the first brake has been applied and before the load comes to rest.

2. In load driving and braking apparatus embodying a prime mover and a slip type drive mechanism having driving and driven elements operatively interposed in power transmitting re lation between the prime mover and the load, the h combination of quick setting brake mechanism operatively connected to that element of the slip drive mechanism which is driven by the prime mover, a delayed action brake mechanism operatively connected to that element of the slip drive mechanism which drives the load, means to energize and fle-energize the prime mover, means to fully apply the first named brake substantially simultaneously with the de-energization of the prime mover to lock the same and the driven element against rotation, and means to partially apply the second named brake after the prime mover and the element connected thereto have come to rest and before the load comes to rest.

3. In load driving and braking apparatus embodying an electric motor prime mover and a two element iiuid coupling operatively interposed in driving relation between the motor and load, the combination of separate electrically controlled brake mechanisms one of which is connected to the driving element of the iluid coupling and the other of which is connected to the driven element thereof, circuits within which are included a source of E. M. F. and said brake mechanisms and said electric motor, and a switch in said circut controlling the motor and the brake mechanisms.

4. In load driving and braking apparatus, the combination with an electric motor prime mover and a fluid coupling having driving and driven elements operatively connected to the prime mover and load respectively, of a delayed action type of brake operatively connected to the driven element of the coupling, means to de-energize the prime mover and hold the driving element against rotation and means to commence the setting of said brake after the electric prime mover has been de-energized whereby at least a part of the energy of the moving load is dissipated in said huid coupling in the form of heat.

5. In load driving and braking apparatus, the combination with an electric motor prime mover and a two element fluid coupling interposed in power transmitting relation between the prime mover and the load and wherein the elec tric motor is connected to the driving element of the uid coupling and the load is operatively connected to the driven element thereof, of a rst electro-magnetic brake mechanism of the quick actingtype operatively connected to the driving element of the iiuid coupling, a second electro-magnetic brake of the delayed action type operatively connected to the driven element of the uid coupling, electric circuits, a source of E. M. F. Within which are included the electric motor prime mover and the electro-magnetic brakes, and a common switch for said circuits.

6, The combination with a load driven by a prime mover through a two element uid coupling, of a rst brake of the quick setting type set by spring means upon deenergizing a solenoid associated therewith, means operatively connecting said first brake to that element of the iiuid coupling which is driven by the prime mover, a second brake of the delayed setting type set by a spring upon cle-energizing a pressure means associated therewith, means operatively connecting the second brake to that element of the Huid coupling which is connected to the load, and means to substantially simultaneously deenergize the prime mover and said solenoid and pressure means associated with said brakes, whereby the prime mover and the element of the coupling driven thereby are brought to a standstill by said quick setting brake prior to the complete setting of the delayed setting brake..

7. In load driving and braking apparatus, the combination with a prime mover and a slip type drive mechanism having a driving element operatively connected to the prime mover and a Y driven elementoperatively connected to theload,

brake mechanism operatively connected to `the driven element of the slip -drive Vmechanism, means to energize and de-energize vthe prime mover, means to hold the de-energized prime mover and its associated driving element against rotation, and means operable after the prime mover and said associated driving element are brought to rest at least partially to set said brake mechanism, whereby at least a part of .the energy o the moving load is dissipated in said Yslip type drive mechanism in the form of heat.

Y U8 References Citedin the le of this patent UNITED STATES -PA'I'ENTS Number Name 'Date Turnbull et a1 Feb. 11, 1930 Neracher et a1 J an, 26,1943 Roche Feb. v5,1946 Dake et a1 May 27, 11947 Dodge VMay 27,1947 

